Metastatic squamous cell carcinoma cells that overexpress c-Met exhibit enhanced angiogenesis factor expression, scattering and metastasis in response to hepatocyte growth factor

We previously performed gene expression pro. ling in a multistep squamous cell carcinoma (SCC) progression model, and identified growth-regulated oncogene-1 (Gro1/KC) as a factor that contributes to enhanced angiogenesis, tumorigenesis and metastasis. In the present study, we explored molecular pathways coactivated with Gro-1/KC, and identified a transcript that encodes c-Met, the receptor for hepatocyte growth factor/scatter factor (HGF). Northern, Western blot, and immunohistochemical analyses confirm that expression of c-Met mRNA and protein is increased with SCC progression. In vitro, HGF preferentially promoted scattering in the metastatic LY-1 and LY-2 lines, and enhanced angiogenesis factors Gro-1/KC and vascular endothelial growth factor (VEGF) production by all tumor cell lines. In vivo, tumor growth and lung metastasis were promoted by transfection and overexpression of HGF cDNA in metastatic LY-1 cells. Our data indicate that metastatic SCC cells that overexpress c-Met exhibit angiogenesis factor expression and enhanced scattering in response to HGF in vitro, and tumorigenesis and metastasis in response to HGF in the tumor microenvironment in vivo.